Urology Flashcards
What are renal tract calculi?
Renal tract calculi/renal stones/urolithiasis are hard masses that form in the urinary tract.
How common are renal tract calculi?
Very common - affect 2-3% of population
Pathophysiology of renal stones?
Over-saturation of urine with certain products.
What are the 4 renal stone types?
- Calcium oxalate & calcium phosphate
- Struvite
- Urate
- Cystine
What are struvite stones formed of?
Magnesium, ammonium and phosphate
What type of renal stone is the most common?
Calcium (80%)
What is the cause of calcium oxalate or calcium phosphate renal stones?
Dietary factors (high purine, high Na, low K), high doses of vitamin D, intestinal bypass surgery and several metabolic disorders can increase the concentration of calcium or oxalate in urine.
Calcium phosphate stones are more common in metabolic conditions, such as renal tubular acidosis.
Describe the appearance of calcium stones on an xray
Spiky, smooth, opaque
What is the most common metabolic abnormality?
Hypercalciuria
Give some risk factors for renal stones
- Low fluid intake
- Urinary tract malformations e.g. horseshoe kidney
- UTIs
- Cystinuria (congenital)
- Hypercalciuria (most common metabolic abnormality)
- Hyperoxaluria
Give some causes of hypercalciuria
- High sodium intake
- 1ary hyperparathyroidism
- Hypervitaminosis D
- Cushing’s syndrome
- Sarcoidosis
- Milk-alkali syndrome
What is the most common presenting feature of renal stones?
Ureteric colic pain (when stone has passed from kidney to ureters).
What causes ureteric colic pain in renal stones?
Caused by increased peristalsis around the site of obstruction
How does ureteric colic pain present?
Sudden onset, severe and radiates from ‘loin to groin’.
Where may the patient be tender on examination in renal stones?
Tender in the flank region
Haematuria, nausea & vomiting may also be present in renal stones. Is the haematuria visible or microscopic?
90% microscopic
There are 3 naturally narrow parts of the ureter. What are they?
- Pelvicoureteric junction (PUJ) → Where the renal pelvis becomes the ureter
- Crossing the pelvic brim → Iliac vessels cross the ureters
- Vesicoureteric junction (VUJ) → where the ureters enter the bladder
What must you rule out if a male >65 presents with abdominal/flank pain?
AAA
What is the triad of symptoms in an AAA?
Hypotension, syncope and back pain
Give some differentials for renal stone presentation
- AAA
- Gallstones
- Ectopic pregnancy
- Pyelonephritis
- Renal infarcts
- Hydronephrosis
- Renal tract malignancy
- MSK
- Shingles
Can use Vitamin D surgical sieve:
Vascular – AAA, renal artery, vein thrombus, mesenteric ischaemia
Infective/Inflammatory – pyelonephritis, colitis, shingles
Trauma – muscle pain, splenic rupture
Autoimmune
Metabolic/Endocrine – renal stones
Iatrogenic/Idiopathic
Neoplasm – renal cancer, bowel cancer
Degenerative – osteoarthritis
What bedside investigations would you perform in suspected renal stones?
- Urinalysis
- Obs
- Pregnancy test (women)
- ECG (rule out cardiac)
- Bedside USS (FAST)
- Glucose
What bloods would you request in suspected renal stones?
- FBC
- U&Es
- LFTs
- CRP
- Renal specific:
- Bone profile
- Magnesium
- Urate
- Thinking AAA:
- Clotting
- G&S/crossmatch
What is the 1st line imaging tool in suspected renal stones (not including women <40)?
CT KUB (no contrast)
Likely blood test results in renal stones:
CT KUP scan showing right sided hydronephrosis
Likely urine dip in renal stones:
Abdominal XR of renal stone and staghorn calculi
What is the cause of struvite renal stones?
UTIs → ammonia produced as waste product by bacteria can make urine more alkaline, leading to struvite stones (proteus → urate producing)
How do struvite stones appear on x-rays?
Staghorn calcifications, radio-opaque
Which type of renal stones appear in a ‘staghorn’ shape on x-rays?
Struvite
What is the least common type of renal stone?
Cystine
What is the cause of urate renal stones?
Hyperuricaemia e.g. diet rich in purine, alcohol, gout, CKD
How do urate renal stones appear on x-rays?
Smooth, brown, radiolucent
Cause of cystine renal stones?
Renal tubular defects
How do cystine renal stones appear on x-rays?
Yellow, semi-opaque
What is given for initial management of renal stones?
- Analgesia +/- antiemetic
- May need IV fluids
- Any signs of infection → antibiotics
Which type of analgesia is most effective at managing renal stone pain?
PR diclofenac
Give some admission criteria for renal stones
Any of the following:
- Renal function deranged (AKI)
- Pain uncontrolled with simple analgesia (requiring morphine)
- Evidence of an infection
- Large stones (>5mm)
- Solitary kidney/previous renal transplant
- Bilateral renal calculi
What is the most common conservative management plan in renal stones if the stones are <5mm?
Stones that are <5mm in diameter have a 95% chance of passing spontaneously (this is only used if there is no evidence of hydronephrosis or renal damage). GIVE ANALGESIA.
What is the name of the interventional radiology used in the treatment of renal stones?
Extracorporeal shock wave lithotripsy (ESWL)
What does ESWL involve?
- Using shockwaves guided by US to break up the stones into smaller fragments
- Must be <2cm
Who can ESWL not be used on?
Pregnant women
Where the stone is on a bony landmark
If there is evidence of significant hydronephrosis and renal damage in renal stones, what may be put in?
Nephrostomy
What are lower urinary tract symptoms (LUTS)?
A group of key symptoms that are often experienced with urinary tract pathology.
What are the 3 broad classifications of LUTS?
Voiding, storage & associated symptoms
Give some storage LUTS
- Increased urinary frequency
- Nocturia
- Urgency
- Incontinence:
- Urge (e.g. in young children)
- Stress (e.g. after childbirth)
Give some voiding LUTS
- Hesitancy/straining
- Poor flow
- Terminal dribble
- Feeling of incomplete emptying
Give some associated LUTS
- Haematuria
- Suprapubic pain
- Colicky pain
What is the most common cause of LUTS in men?
Benign prostate hypertrophy
What is the most common cause of LUTS in women?
UTIs
Give some differential diagnoses for LUTS
-
Prostate:
- Benign prostate hypertrophy (BPH)
- Acute/chronic prostatitis
- Prostate cancer
-
Bladder:
- UTIs
- Bladder cancer
- Detrusor muscle weakness/instability
- Neurological disease (MS, spinal cord injury)
- Polyuria
-
Urethra:
- Urethral stricture
- Malignancy
-
External:
- Menopause
- External compression (e.g. pelvic tumour, faecal impaction)
What bedside investigations would you do in LUTS?
- Pre & post void bladder scan
- Urine dip
- PT
- DRE
- Blood glucose
What bloods would you do in LUTS?
- FBC
- U&Es
- LFTs
- CRP
- HbA1c
- PSA
- VBG
- G&S
- Clotting
What imaging would you most likely do in LUTS?
US or CT KUB
What is PSA?
Prostate specific antigen → a protein secreted by normal prostatic epithelial cells and cancerous prostate cells
What is the function of PSA?
To liquefy semen allowing spermatozoa to move more freely
What can PSA blood levels indicate?
- Small amounts of PSA are present in the blood
- As a result of altered prostate architecture in prostate cancer/BPH, more PSA leaks out and increases the levels in the blood
What is the aim of a PSA test?
Early detection of prostate cancers
Which signs & symptoms may indicate the need for a potential PSA test?
- LUTS e.g. nocturia, frequency, hesitancy, urgency or retention
- Erectile dysfunction
- Visible haematuria (painless, visible haematuria is cancer until proven otherwise)
- Unexplained symptoms that could be due to advanced prostate cancer e.g. lower back pain, bone pain, weight loss
What are some other factors that can cause a raised PSA?
BPH, UTI, vigorous exercise (cycling), ejaculation and recent prostate examination
Why are PSA tests not always the best test?
- Other factors can cause a raised PSA
- False negatives - 15% of men with a negative PSA may have prostate cancer
- False positives - 75% of men with a positive PSA will go on to have a negative prostate biopsy
What % of men with a positive PSA will go on to have a negative prostate biopsy?
75%
What are some conservative management options for LUTS?
- Regulating fluid intake
- Urethral milking/double voiding
- Pelvic floor exercises
- Bladder training
What are the 2 most common medications used in the treatment of LUTS in BPH?
- Alpha blockers
- 5a-reductase inhibitors
What is an example of an alpha blocker?
Tamsulosin
What is an example of a 5a-reductase inhibitor?
Finasteride
What is the function of alpha blockers?
Relax prostatic muscle to aid urination
What is the function of 5a-reductase inhibitors?
Reduce testosterone production in order to shrink prostate
How can anticholinergics be used in the treatment of LUTS?
Help in urinary incontinence (overactive bladder) by relaxing the detrusor muscle.
Potential complication of BPH?
- Renal and bladder calculi due to stagnation of urine
- Chronic obstruction → bladder wall hypertrophy/distension → overflow incontinence/bilateral hydronephrosis → renal failure
- Acute urinary retention may also occur
Define acute urinary retention
A new inability to pass urine with significant residual volumes (usually <500ml). This leads to pain and discomfort, with significant post-void residual volumes.
Who is acute urinary retention most common in?
Most prevalent in older male patients, due to enlarged prostate leading to bladder outflow obstruction, however there are a wide array of potential causes.
What is the immediate management of acute urinary retention?
Catheterisation
What are the 2 major complications of acute urinary retention?
- AKI
- Post-obstructive diuresis
What is post-obstructive diuresis?
The condition of prolonged urine production of at least 200ml for at least two consecutive hours immediately following the relief of urinary retention or similar obstructive uropathy.
What type of tumour are most prostate cancers?
Adenocarcinomas
What staging system is used in prostate cancer?
TNM (tumour, node, metastasis)
What grading system is used in prostate cancer?
Gleason scale
Risk factors for prostate cancer?
- Age
- Ethnicity → men of Black African or Caribbean ethnicity are 2x more likely (1 in 4)
- Family history
Which genes are implicated in prostate cancer?
BRCA1 or BRCA2
What zone do over 75% of prostate adenocarcinomas arise from?
Peripheral zone (20% in transitional zone, 5% in central zone)
What type of cells do prostate cancers arise from?
Acinar (glandular) or ductal cells
Are LUTS an early or late sign of BPH? Of prostate cancer?
BPH → early sign
Prostate cancer → late sign
What zone does BPH arise from?
It is a generalised enlargement of the transitional zone
What is a tumour grade?
Tumour grade is the description of a tumour based on how abnormal the tumour cells and the tumour tissue look under a microscope
What makes up the Gleason score?
Sum of the most common growth pattern + Second most common growth pattern seen on biopsy
What does a higher Gleason score indicate?
Poorer prognosis
What is the lowest Gleason score that can be assigned to prostate cancer?
3 + 3